Habonim Catalog Interactive 2024 V04 15022024 - Catalog - Page 28
VALVE FEATURES
Stem Design
A crucial component in a quarter-turn ball valve is the stem, which transfers the torque from
the operator to rotate the ball and control its movement. The stem geometry and surface
finish is crucial to minimize stem leak and maximize ease of operation. The stem is a dynamic
element and, in most cases, is the only element that protrudes from the pressure vessel
and is thus subject to safety issues as well. Habonim’s robust stem design complies with
ASME B16.34 and API 6D and can endure at least twice the valve’s nominal torque. To solve
a major safety issue, the stem is designed to be “blowout-proof". Because it is inserted into
the valve body from within, the stem will not release under pressure. All Habonim stems are,
by default, fire-safe design. A special chamfer is machined at the root of the stem so that,
in the event of fire, the stem is pushed upwards and seals against the valve body - metal
to metal engagement. Various stem materials are available, from austenitic stainless steel
to nickel alloys, to titanium for light and moderate torque requirements, and for high cycle
applications or high torque demands. The stem top planes for valve sizes ½" (DN15) up to
2½" (DN65) are typically a Double-D shape, while 3" (DN80) stems and above typically have
a square shaft (although a Double-D stem can be provided upon request by adding the 'WR'
suffix to the valve description).
Anti-Static Design
An anti-static device provides for electrical continuity between the body, ball and shaft of the
valve and is used to discharge static electricity buildup on electrically isolated balls. According
to the EN ISO 17292 standard, all valves with a size up to 2" (DN ≤ 50) require a stem/body
contact, while larger valve sizes also require a ball/stem contact. The anti-static feature shall
have electrical continuity across the discharge path with a resistance not exceeding 10 Ω from
a power source not exceeding 12 VDC when type tested on a new, dry, as‐built valve after
pressure testing and cycling of the valve at least five times. The Habonim anti-static device, in
which contact is made via a spring loaded stainless steel element, complies with EN ISO 17292
and is, in fact, built-in to all Habonim valve product lines, without exception.
Anti-static design
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VALVES
Stem design
